JP2001273039A - Variable pressure pilot relief valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable pressure pilot relief valve in which a switching valve that has flow rate controlling function and is made with reduced cost, is connected to an water exit. SOLUTION: The variable pressure valve is composed of a main valve 14 that is driven by a piston 18, a water-stopper valve 21 of which down-stream side is connected to an orifice 23, a pilot passage 24 to transmit water pressure through the orifice 23 to a piston room 20, a ball valve 25 to adjust pressure in a pilot passage 24 and a solenoid to drive and control a water-stopper valve 21 and a ball valve 25. By energization of the solenoid, the ball valve 25 is closed and the water-stopper valve 21 is opened, resulting in high pressure water entry into the piston room 20, leading to the movement of the piston 18 and finally to the opening of the main valve 14. The water flow amount is so controlled that the ball valve 25 controls the pressure in the piston room 20 at a constant level according with the solenoid current intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pilot variable pressure control valve, and more particularly to a control valve for supplying water at a controlled flow rate to a nozzle unit having a nozzle for discharging water for local cleaning at a cleaning valve seat. The present invention relates to a pilot variable pressure control valve.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing a schematic configuration example of a flow rate control unit in a conventional cleaning valve seat. The flow control unit in the cleaning valve seat includes, for example, a filter 1, a check valve 2, a water stop valve 3, an electromagnetic valve 4, a constant pressure valve 5, and a switching valve 6. The filter 1 is arranged at a water inlet connected to a water supply pipe. The check valve 2 on the downstream side is integrally formed with a water stop valve 3 which is manually opened and closed. The solenoid valve 4
It is a valve that opens and closes a water passage, and the constant pressure valve 5 has a function of making the pressure on the downstream side constant regardless of the water pressure of the tap water,
The switching valve 6 has a function of branching water to three outlets by a stepping motor and adjusting a flow rate of each outlet. The three water outlets are the three water outlets of the nozzle unit to which the tip is connected, that is, the first port for washing the hips which discharges vigorously, the second port for cleaning the hips which discharges softly, and the bidet cleaning. Connected to the passages respectively leading to the third ports. The switching valve 6 can be switched so as to independently supply constant-pressure water to the three water outlets, or to simultaneously discharge water from the three water outlets.

[0003] The water introduced into the water inlet is filtered by a filter 1 and is controlled on / off by a solenoid valve 4 via a check valve 2 and a water stop valve 3. The water whose ON is controlled by the solenoid valve 4 is adjusted to a constant water pressure by the constant pressure valve 5, and finally, the water is switched to the water outlet desired by the user by the switching valve 6 and is discharged. At this time, the flow of water is adjusted to a flow rate desired by the user by controlling the position of the switching valve 6 by a stepping motor. The water whose flow rate has been adjusted is guided to the nozzle and discharged from any one of the first to third ports. After use, the switching valve 6 is controlled so that water is simultaneously discharged from the three water outlets, and the nozzle is cleaned.

[0004]

As described above, in the flow control section of the conventional cleaning valve seat, the switching valve connected to the nozzle switches the water to each water outlet, adjusts the flow rate at each water outlet, Since the function of simultaneous water discharge to the water outlet is controlled by the stepping motor, there is a problem that the cost of the switching valve increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a pilot variable pressure control valve which has a flow rate adjusting function of a switching valve in a flow rate adjusting section and can reduce the cost of the switching valve. The purpose is to provide.

[0006]

According to the present invention, in order to solve the above-mentioned problems, in a pilot variable pressure control valve for controlling a flow rate of a fluid, an upstream side of a valve seat formed in a flow passage for receiving a high-pressure fluid is provided. A main valve, which is arranged to be seated from and communicates with an outlet of a fluid whose flow rate is controlled on the downstream side,
A piston that is inserted and disposed in a cylinder coaxial with the main valve on the downstream side of the main valve and drives the main valve from the downstream side, and is formed at a location communicating with a flow path on the upstream side of the main valve. An on-off valve arranged so as to be seated from the upstream side on a valve seat having an orifice formed between the valve stem and a piston chamber located on the back side of the piston as viewed from the main valve, and a downstream side of the on-off valve , A flow control valve for controlling an amount of fluid leaking from the pilot passage, an opening / closing operation of the on-off valve, and a differential pressure between the upstream side and the downstream side of the flow control valve become constant. And a solenoid for adjusting the opening of the flow control valve as described above.

According to such a pilot variable pressure control valve, when the solenoid is not energized, the main valve and the on-off valve are closed by the high-pressure fluid on the upstream side, respectively.
No fluid flows downstream of the main valve. Here, when the solenoid is energized, the on-off valve opens, high-pressure fluid flows into the pilot passage through the orifice of the on-off valve, and further flows into the piston chamber through this pilot passage. As the pressure in the piston chamber increases, the piston moves toward the main valve, and drives the main valve in the valve opening direction. As a result, the main valve opens, and high-pressure fluid flows out to the fluid outlet via the main valve. At this time, the flow regulating valve is driven to the fully closed position by the solenoid immediately after the solenoid is energized.After that, the flow regulating valve opens by the pressure in the pilot passage, and the pressure in the pilot passage and the driving force by the solenoid are reduced. Is set at an opening that balances the pressure, and thereafter, control is performed so that the differential pressure between the pressure in the pilot passage and the pressure on the downstream side becomes constant. This means that the pressure in the piston chamber is kept constant at a certain value, thereby keeping the flow rate of the fluid flowing through the main valve at a certain value. When the driving force of the solenoid is changed in this state,
Since the pressure in the piston chamber is controlled to the corresponding pressure, the main valve changes accordingly, and the flow rate of the fluid flowing through the main valve also changes. As described above, by providing the functions of opening and closing the fluid flow path and adjusting the flow rate, it is possible to employ a simple switching valve having no flow rate adjusting function as a valve connected to the outlet.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking as an example a case where the present invention is applied to a flow control unit of a cleaning valve seat.

FIGS. 1 and 2 are sectional views showing the configuration of a pilot variable pressure control valve according to a first embodiment of the present invention. In particular, FIG. 1 shows a valve arrangement state when the solenoid is turned off, and FIG. 2 shows a valve arrangement state when the solenoid is turned on.

The pilot variable pressure control valve according to the present invention comprises a water inlet 11 connected to a water supply pipe via a filter and a water stopcock (not shown), and a water outlet 12 connected to a nozzle via a switching valve (not shown). And a drain outlet 13 to which a hose for guiding water used for flow rate adjustment into the toilet bowl is connected.

A main valve 14 is provided downstream of the water inlet 11 and is fitted to a valve seat 15 so as to be reciprocally movable in the axial direction. The downstream side of the main valve 14 communicates with the water outlet 12. A ring-shaped packing 16 made of an elastic material is fitted on the upstream side of the main valve 14. The spring 17 disposed on the upstream side of the main valve 14 urges the packing in a valve closing direction to cause the packing. 16 is pressed against the valve seat 15 to be in a fully closed state.

Downstream of the main valve 14, a cylinder having an inner diameter larger than the inner diameter of the valve seat 15 is formed on an extension of the axis thereof, and a piston 18 is reciprocally movable in the axial direction in the cylinder. Are inserted and arranged. The downstream end surface of the main valve 14 is in contact with the end surface of the piston 18 facing the main valve 14, and a V-ring 19 is provided on the outer periphery of the piston 18 so as to form a seal with the inner wall surface of the cylinder. The space on the opposite side of the piston 18 forms a piston chamber 20.

Further, there is provided a water stop valve 21 which is branched from a space communicating with the water inlet 11 and is arranged so as to move in a direction perpendicular to the axis of the main valve 14. This water stop valve 21
It is urged in the valve closing direction by a spring 22 arranged on the upstream side. The through hole provided in the valve seat so that the valve shaft of the water stop valve 21 is fitted and inserted has an inner diameter larger than the outer diameter of the valve shaft, and an orifice 23 is formed between the through hole and the valve shaft. . The downstream side of the water stop valve 21 is the pilot passage 2
4 communicates with the piston chamber 20. Water stop valve 2
The one valve shaft penetrates the pilot passage 24 and is inserted and disposed in a valve seat of a ball valve 25 provided further therefrom. In addition, the valve shaft of the water stop valve 21 has a length such that when the water stop valve 21 is in a fully closed state, an end surface comes to a position protruding from a valve seat of the ball valve 25.

The ball of the ball valve 25 is fixed to a shaft 26 operated by a solenoid. The solenoid includes an electromagnetic coil 27, a movable iron core 28, a fixed iron core 29, and a spring 30. When the electromagnetic coil 27 is not energized, the movable iron core is urged in a direction away from the ball valve 25 by the spring 30 as shown in FIG. 1, and when the electromagnetic coil 27 is energized, as shown in FIG. 28 is a fixed iron core 29
And moves in a direction approaching the ball valve 25. The shaft 26 having a ball fixed to one end is fitted and disposed on a fixed iron core 29, and the other end is fixed to a movable iron core 28.
That is, the opening of the ball valve 25 is controlled by the movable iron core 28. On the downstream side of the ball valve 25, there are gaps forming leak paths between the fixed iron core 29 and the shaft 26 and between the movable iron core 28 and the cylinder storing the same. Communicates with the drain outlet 13. That is, the downstream side of the ball valve 25 is at the atmospheric pressure.

The inner diameter of the through hole provided in the valve seat of the water stop valve 21 is at least three times the distance that the valve body separates from the valve seat when the through hole is fully opened. Thereby, the pressure inside the water stop valve 21 becomes almost equal to the water inlet pressure,
Since the water pressure is added to the diameter of the valve shaft,
The force for urging 1 toward the solenoid is reduced, and the influence on the control of the ball valve 25 can be reduced.

As described above, the water stop valve 21 and the ball valve 2
5 is operated by a solenoid.
1, the ball valve 25, and the relationship between the solenoid will be described. For the sake of simplicity, it is assumed that the pressure of tap water supplied to the water inlet 11 is constant without fluctuating.

FIG. 3 is a diagram showing the relationship between the solenoid current and the opening of the water shutoff valve. In this figure, the horizontal axis represents the solenoid current i flowing through the electromagnetic coil 27, and the vertical axis represents the opening of the water stop valve 21.

First, when the solenoid current i = 0, since the movable iron core 28 is urged toward the drain outlet 13 by the spring 30, the water stop valve 21 is fully closed. At this time, as shown in FIG. 1, the ball valve 25 is in a fully open state, and the downstream side of the water stop valve 21 is at atmospheric pressure.

Here, when the solenoid current i = i1 flows, the movable iron core 28 is attracted and moves toward the fixed iron core 29, so that the water stop valve 21 is fully opened. In addition,
The ball is seated on the valve seat of the ball valve 25 immediately after the solenoid is energized. Thereafter, the suction force of the solenoid and the pressure of water flowing into the piston chamber 20 through the orifice 23 of the water stop valve 21 are balanced. The opening of the position.

As described above, in this pilot variable pressure control valve, the water stop valve 21 is controlled by turning on / off the solenoid current, and thus constitutes an on / off solenoid valve.

FIG. 4 is a diagram showing the relationship between the solenoid current and the pressure in the piston chamber. In this figure, the horizontal axis represents the solenoid current i flowing through the electromagnetic coil 27, and the vertical axis represents the pressure in the piston chamber.

First, when the solenoid current i = 0, FIG.
As shown in (2), since the movable iron core 28 is urged toward the drain outlet 13 by the spring 30,
1 is fully closed by the spring 22 and the water pressure of the tap water, and is shut off from the water pressure. On the other hand, since the ball valve 25 is in the fully opened state, the pressure in the piston chamber 20 is equal to the atmospheric pressure P0.
It is in the state equal to.

Here, when the solenoid current i = i1 flows, as shown in FIG. 2, the movable iron core 28 is attracted and moves toward the fixed iron core 29, and the water stop valve 21 is fully opened. As a result, water flows through the water stop valve 21, and the pressure in the piston chamber 20 increases. The pressure at this time is a pressure P1 obtained by subtracting the pressure reduction due to the leakage of water through the ball valve 25 from the pressure in the pilot passage 24. Therefore, the ball valve 25 constitutes a differential pressure valve that keeps the difference between the piston chamber 20 and the atmospheric pressure constant at a pressure determined by the solenoid current. The small amount of water that has passed through the ball valve 25 is drained from the drain outlet 13 via a leak path.

When the solenoid current i is further increased,
The suction force of the movable iron core 28 to the fixed iron core 29 increases, and the solenoid is driven in the direction to close the ball valve 25 via the shaft 26, so that the opening of the ball valve 25 gradually decreases. . Accordingly, the amount of water leaking through the ball valve 25 decreases, and the pressure in the piston chamber 20 increases accordingly.

After being turned on at the solenoid current i = i1, the pressure in the piston chamber 20 is controlled in accordance with the solenoid current i. The lower limit of the control range is a current i0 smaller than the current i1 at the time of turning on, and the current i0 or less is a range where the solenoid is turned off.

Next, the operation of the pilot variable pressure control valve will be described. When the solenoid is not energized, as shown in FIG.
Is closed, so that the water at the inlet 11 is
No spill to 2

When the solenoid is energized by the current i, the water shutoff valve 21 is fully opened and the ball valve 25 is fully closed as shown in FIG. When the water stop valve 21 is opened, water flows through the orifice 23 to the downstream side of the water stop valve 21. This water enters the piston chamber 20 through the pilot passage 24 and applies a load to the back side of the piston 18 as viewed from the main valve 14. At the same time, when the pressure of the water flowing into the downstream side of the water stop valve 21 increases, and a difference between the pressure in the pilot passage 24 and the pressure on the downstream side of the ball valve 25, that is, the atmospheric pressure, becomes a certain value. The pressure in the pilot passage 24 pushes up the ball of the ball valve 25 from the valve seat, and the water in the pilot passage 24 passes through the ball valve 25 so that the difference is constant. The water that has passed through the ball valve 25 is discharged from the drain outlet 13 through a leak path in the solenoid. Thereby, the pressure of the piston chamber 20 becomes
The solenoid is controlled to a constant pressure determined by the current i.

On the other hand, the piston 18 moves in the axial direction due to the difference between the pressure in the space communicating with the water outlet 12 and the pressure in the piston chamber 20. When the main valve 14 is closed, the pressure downstream thereof is approximately atmospheric pressure. For this reason, the water stop valve 2
When the pressure in the piston chamber 20 is increased by the water supplied through the first and pilot passages, the piston 18 moves toward the main valve 14. Since the end face of the main valve 14 is in contact with the piston 18, the piston 18 pushes the main valve 14 in the valve opening direction. As a result, the main valve 14 opens,
Water at the water inlet 11 flows to the water outlet 12 through the main valve 14. As a result, the pressure in the space communicating with the water outlet 12 of the piston 18 increases, and a force acts to push the piston 18 back toward the piston chamber 20. Then, the pressure in the piston chamber 20 increases, but the ball valve 25 operates so as to keep this pressure constant, and the water in the pilot passage 24 communicating with the piston chamber 20 flows out to the drain outlet 13. The main valve 14 moves toward the piston chamber 20 and accordingly moves in the valve closing direction. Main valve 14
Is closed, the amount of water passing through the main valve 14 is reduced. As a result, the pressure of the space on the side of the piston 18 communicating with the water outlet 12 decreases, and the piston 18 moves toward the main valve 14, and the force for moving the main valve 14 in the valve opening direction is increased. work. In this way,
The opening of the main valve 14, that is, the water outlet 12 is located at a position where the pressure in the piston chamber 20 and the pressure on the downstream side of the main valve 14 are balanced.
Is controlled.

Thus, the main valve 14 is connected to the piston chamber 2
0 is controlled to a valve opening determined by the pressure of 0, and the pressure of the piston chamber 20 is controlled by the opening of the ball valve 25, so that the water at the water inlet 11 is controlled to a flow rate corresponding to the suction force of the solenoid. Output from the water outlet 12.

When the solenoid current i is increased in this state,
Since the suction force of the solenoid is increased and the pressure in the piston chamber 20 is controlled to a higher pressure, the main valve 14 is moved in the opening direction, and the flow rate outputted from the water outlet 12 is controlled to be increased. Become.

Here, the effective pressure receiving area of the main valve 14 is S _A ,
The effective pressure receiving area of the piston 18 is S _B (> S _A ), and the water inlet 1
Assuming that the pressure of 1 is P _IN , the pressure of the water outlet 12 is P _OUT , the pressure of the piston chamber 20 is P _X , and the force for biasing the main valve 14 in the valve closing direction is F, the main valve 14 opens. The force relationship when balancing between the direction and the closing direction is

[0032]

## EQU1 ## (P _X -P _OUT ) S _B = (P _IN -P _OUT ) S _A + F (1) In this equation (1), the left side represents the force acting in the direction in which the main valve 14 opens, and the right side represents the force acting in the direction in which the main valve 14 closes. From this equation (1), the water outlet 1
The pressure of 2 is

[0033]

P _OUT = (F + S _A · P _IN -S _B · P _X ) / (S _A -S _B ) (2) In this equation (2), S _A , S _B , and F are fixed values determined at the time of design, whereas P _IN is a value that varies depending on where water is drawn, and P _X is determined by the suction force of the solenoid. Value. However, since P _X is the user to adjust the attraction force of the solenoid so that the water pressure desired, as P _IN is changed, because the user to adjust the P _X accordingly, the change in P _IN is the problem Absent. Eventually, the pressure P _OUT of the water outlet 12 is changed by the suction force of the solenoid adjusted by the user, that is, the solenoid current, so that the water discharge flow rate is changed by the solenoid current.

The water whose flow rate has been adjusted as described above is finally supplied to a switching valve, and the switching valve switches the passage so that the nozzle unit has a first mouth for washing the buttocks that vigorously discharges water. The water is guided to the second mouth for washing the buttocks, which discharges water softly, or the third mouth for washing the bidet.
For this reason, the switching valve only needs to have a function of switching the water whose flow rate has been adjusted, so that a switching valve having a simple structure can be used.

FIGS. 5 and 6 are sectional views showing the configuration of a pilot variable pressure control valve according to a second embodiment of the present invention. FIG. 5 shows a valve arrangement state when the solenoid is turned off, and FIG. 6 shows a valve arrangement state when the solenoid is turned on. In FIGS. 5 and 6, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The difference from the pilot variable pressure control valve of the first embodiment lies in the sealing portion of the piston 18. That is, in the pilot variable pressure control valve of the first embodiment, the piston 18 and the cylinder accommodating the piston 18 are sealed by the V ring 19,
In the pilot variable pressure control valve of the embodiment, the control is performed by the piston ring 31.

The purpose of the V-ring 19 is to completely prevent water leakage between the space leading to the water outlet 12 and the piston chamber 20, but has the property of high sliding resistance. On the other hand, the piston ring 31 has a very small sliding resistance and can move the piston 18 smoothly, but has a property that some water leaks from the ring because a part of the ring is broken. However, even if water leaks from the piston chamber 20 to the space having a small pressure leading to the water outlet 12, the leaked water flows out of the water outlet 12 together with the water whose flow rate is controlled by the main valve 14, so that there is no problem. No problem.

Although the present invention has been described in detail with reference to a preferred embodiment, the present invention is not limited to this particular embodiment, and various changes and modifications are possible within the spirit of the present invention. It is. For example, a filter and a water stopcock may be integrally provided on the water inlet side, and an overflow valve for draining overflow water as drain may be integrally provided on the water outlet side. Further, the leak path formed on the downstream side of the ball valve may be formed so as to be directly guided to the drain outlet without passing through the solenoid.

[0039]

As described above, according to the present invention, the function of turning on / off the pilot variable pressure control valve is provided by the water stop valve, and the function of adjusting the flow rate is provided by the ball valve, and the function is turned on / off. The function and the flow rate adjusting function are controlled by the attraction force of the solenoid, that is, the solenoid current. As a result, in the nozzle unit of the washing valve seat connected to the pilot variable pressure control valve, there is no need to perform flow control and water path switching by an expensive stepping motor as a switching valve for switching the water path to each nozzle. Since a switching valve that only switches can be adopted, the cost of the cleaning valve seat can be reduced.

Further, since the control valve is configured as a single control valve having the functions of the conventional water stop valve, solenoid valve and constant pressure valve together with the flow control function, it becomes a more compact pilot variable pressure control valve, and the water in the washing valve seat is reduced. The control mechanism can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a pilot variable pressure control valve according to a first embodiment of the present invention when not operating.

FIG. 2 is a cross-sectional view illustrating a configuration of the pilot variable pressure control valve according to the first embodiment of the present invention during operation.

FIG. 3 is a diagram showing a relationship between a solenoid current and an opening degree of a water stop valve.

FIG. 4 is a diagram showing a relationship between a solenoid current and a pressure in a piston chamber.

FIG. 5 is a cross-sectional view illustrating a configuration of a pilot variable pressure control valve according to a second embodiment of the present invention when not operating.

FIG. 6 is a cross-sectional view showing a configuration during operation of a pilot variable pressure control valve according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating a schematic configuration example of a flow control unit in a conventional cleaning valve seat.

[Explanation of symbols]

 Reference Signs List 11 water inlet 12 water outlet 13 drain outlet 14 main valve 15 valve seat 16 packing 17 spring 18 piston 19 V-ring 20 piston chamber 21 water stop valve 22 spring 23 orifice 24 pilot passage 25 ball valve 26 shaft 27 electromagnetic coil 28 movable iron core 29 Fixed iron core 30 Spring 31 Piston ring

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16K 31/42 F16K 31/42 A F term (Reference) 3H056 AA02 BB07 BB10 BB32 CA02 CA14 CB03 CB07 CB08 CC03 CC07 CC12 CC18 CD01 CE01 DD02 EE06 GG05 3H059 AA06 AA15 BB05 BB22 CA12 CA15 CB12 CD04 CD11 CE04 DD01 DD07 DD13 DD14 EE13 FF02 3H106 DA02 DA05 DA22 DB02 DB22 DB32 DC04 DD05 EE34 FB08 FB11 FB12 HH05 EE20 5G BB09 BB09 KK02 KK08 LL05

Claims (8)

[Claims] 1. A pilot variable pressure control valve for controlling a flow rate of a fluid, wherein the pilot variable pressure control valve is disposed so as to be seated from an upstream side on a valve seat formed in a flow path for receiving a high-pressure fluid, and the flow rate is controlled on a downstream side. A main valve to which a fluid outlet is communicated; a piston which is inserted and disposed in a cylinder coaxial with the main valve at a downstream side of the main valve to drive the main valve from a downstream side; An on-off valve that is formed at a location that communicates with the flow path on the upstream side and that is arranged so as to be seated from the upstream side on a valve seat where an orifice is formed between the valve stem and the valve stem; A pilot passage communicating between a piston chamber located at a position downstream of the on-off valve and a flow control valve for controlling an amount of fluid leaking from the pilot passage; and an opening / closing operation of the on-off valve and an upstream of the flow control valve. Difference between side and downstream And a solenoid for adjusting the opening of the flow control valve so that the pressure becomes constant. 2. The valve according to claim 1, wherein the solenoid opens the on-off valve with a solenoid current greater than a predetermined value, and adjusts the opening of the flow regulating valve with an arbitrary solenoid current greater than a predetermined value. 2. The pilot variable pressure control valve according to 1. 3. The variable pilot pressure control valve according to claim 2, wherein the flow control valve is a ball valve having a ball disposed downstream. 4. The on-off valve, the flow control valve, and the solenoid are arranged on the same axis, and the on-off valve has the valve rod extending through a valve seat of the flow control valve when the valve is closed. 4. The pilot variable pressure control valve according to claim 3, wherein when the valve is opened, the valve stem is driven via a shaft extending from the solenoid and a ball of the ball valve. 5. The pilot variable pressure control valve according to claim 1, wherein the main valve and the on-off valve each include a spring for urging each pair of valves from an upstream side in a valve closing direction. 6. The piston according to claim 1, wherein a V ring is provided around the piston to seal with the cylinder.
The pilot variable pressure control valve as described. 7. The pilot variable pressure control valve according to claim 1, wherein the piston is provided with a piston ring to seal the cylinder. 8. The variable pilot pressure control valve according to claim 1, wherein a leak path for discharging the fluid leaked by the flow control valve to the outside is formed in the solenoid.